It just changes the way swords look in hand.
- Open your Minecraft launcher.
- Open the “Options” menu near the “login” button
- Use the link in the Options menu to open the .minecraft directory
- Navigate to the bin folder.
- Open minecraft.jar and the HandSword version you downloaded with appropriate archive software. (i.e WinRAR, 7-Zip)
- Drag all contents from HandSword into the minecraft.jar
- Delete the META-INF folder from the minecraft.jar
- Close both minecraft.jar and HandSword download.
- Go back to the .minecraft directory.
(The mod edits a base class and requires no APIs. It was built with Minecraft Forge, but it should work without it)